Astronomy Colloquium

There is now strong evidence that many and possibly most stars form in clusters, rather than individually. This means that most of the massive stars that we observe in galaxies have, at some point, lived in a star cluster, and that the life cycle of star clusters tells us about the build up of galaxies. Motivated by observations of nearby spirals, mergers, and starburst galaxies taken with the Hubble Space Telescope, I will discuss recent results which address the following
issues: (1) The mass and age distributions of star clusters tell us about the formation and disruption of the clusters. Are these distributions similar in different galaxies? (2) High mass x-ray
binaries (HMXB), where either a black hole or neutron star is closely orbited by a massive star, trace recent star formation in galaxies, and are often found close to star clusters. What is the relationship between HMXBs and star clusters? (3) The inter-arm regions of spiral galaxies emit diffuse, ultraviolet light. Are low mass star clusters responsible for this emission?